A female presents with anorexia, weight loss, hyperpigmentation, bowel changes, and light headedness on standing. The cosyntropin stimulation test shows random serum coisol of 11 mcg/dL (normal is greater than or equal to 20 mcg/dL). Serum coisol 1 hour after 0.25 mg cosyntropin N is 14 mcg/dL. (The rise in coisol is expected to be > 7 mcg/dL). Aldosterone level is 10 ng/dL. Which of the following is an appropriate treatment for this patient?